[OSM-dev] PostGIS & Mapnik problem
colm.mcmullan at gmail.com
Thu Jan 14 18:18:16 GMT 2010
Thanks for the help. That was sound advice, working backwards from
generate_image.py and the osm.xml was quick and easy. Definitely a good
I think the two problems I had were that the datasource is spherical
mercator so I changed the srs of the layer but also I think that I needed to
use the m.zoom_to_box(bbox)function in the code, otherwise I'm guessing it
tries to render a whole world view so my little insignificant streets in
London wouldn't even register at pixel level :)
Works a charm now it seems.
On Wed, Jan 13, 2010 at 13:57, Andy Allan <gravitystorm at gmail.com> wrote:
> On Wed, Jan 13, 2010 at 1:12 PM, Colm McMullan <colm.mcmullan at gmail.com>
> > <Map bgcolor="#ffffff" srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0
> > +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs -tl
> > <Style name="line style 2">
> > <Rule>
> > <LineSymbolizer>
> > <CssParameter
> > <CssParameter
> > </LineSymbolizer>
> > </Rule>
> > </Style>
> > <Layer name="layer 4" srs="+proj=latlong +ellps=WGS84 +datum=WGS84
> > +no_defs" status="on">
> > <StyleName>line style 2</StyleName>
> > <Datasource>
> > <Parameter name="type">postgis</Parameter>
> > <Parameter name="host">localhost</Parameter>
> > <Parameter name="user">postgres</Parameter>
> > <Parameter name="dbname">gis</Parameter>
> > <Parameter name="estimate_extent">true</Parameter>
> > <Parameter name="table">planet_osm_roads</Parameter>
> > </Datasource>
> > </Layer>
> > </Map>
> > So I'm a bit stumped, what am I missing? Has anyone got any suggestions?
> My rule of thumb with Mapnik is "it's always a projection problem".
> Are you sure that your db is in latlong? By default osm2pgsql is in
> spherical mercator.
> If that's not it, I'd suggest starting with the generate_image.py and
> the osm.xml from OSM SVN, and get that working with all the defaults
> as described on the wiki. You can then step through changes one at a
> time (e.g. changing your db to latlong instead of spherical mercator,
> using your own style instead of osm.xml and so on.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the dev